This invention relates to an electronic musical instrument with an automatic chord performance device capable of simultaneously performing chord tones which are different in tone color by controlling generation of the chord tones in different tone colors in accordance with automatic chord performance patterns of plural systems.
Automatic chord performance devices in a prior art electronic musical instrument are so constructed that a single train of chord tone generation timing signal is generated in accordance with a selected rhythm and the timing for generating tones of the chord which is formed by key depression is controlled by this single train of chord tone generation timing signal.
If it is desired to perform chord tones in different tone colors simultaneously in such prior art devices employing a single train of chord tone generation timing signal, chord tones in any of the available tone colors are generated at the same timing. As a result, the musical performance becomes monotonous and a desirable musical effect which is expected to be derived from performance of the chord tones in plural tone colors can hardly be attained. Suppose, for example, that chord tones of a piano tone and chord tones of a guitar tone are played simultaneously. The two tone colors of chords should preferably be generated at different timing so that characteristics of the piano tone and those of the guitar tone can be fully appreciated by the audience. Despite such requirement, the two tone colors of chords are actually generated simultaneously in those prior art devices with a resulting impaired musical effect in the performance of some musical pieces.
The prior art automatic chord performance devices employing only a single train of chord tone generation timing signal are disadvantageous not only in the simultaneous performance of chords in plural tone colors but also in playing of chord tones in a single tone color. If, for example, a rhythm of a quick tempo is selected, generation of chord tones of a single tone color is controlled by a single chord tone generation timing signal in this quick tempo. In this case, as the tempo becomes quick, interval of pulses of this train of chord tone generation timing signal becomes short even to such an extent that before a decaying portion of one time of chord tones which are controlled to be generated is finished, generation of the next time tones is started. This causes cancellation of the decaying portion of the first chord tones with a result that chord tones having a sufficient long decaying effect cannot be obtained.